Using the first-principles calculations, we investigate the geometric, electronic and magnetic properties of armchair silicene nanoribbons with different edge hydrogenations. Our results show that the interesting magnetic behaviors such as the bipolar magnetic semiconductor can be found. Moreover, the addition of the transverse electric field can modulate the bipolar magnetic semiconductor to half-metal or spin-splitting metal. And the spin-up electrons are localized at one edge, the spin-down holes localized at the opposite edge under the external electric field. These results may present a new avenue for band engineering of silicene nanoribbons and benefit the design of silicon-based nano-spin-devices in nanoelectronics.